Input Description

EN (enable)

Data type: BOOL

The Function Block is activated (EN = TRUE) or deactivated (EN = FALSE) via input EN. If the block is active, the current values are available at the outputs. To start a new write job the input EN has to be set from FALSE to TRUE.

If the input values are valid, a request to perform a MODBUS job is sent to the Communication Block via the DRIVE_DATA variable. If at least 1 input is invalid, no job is generated and the error is displayed at the outputs ERR and ERNO instead.

START (start)

Data type: BOOL

With a rising edge at input START (FALSE -> TRUE) the ACS Drive is started. If START = FALSE the drive is stopped along the normal stop ramp, defined in the drive (e.g. Par. 22.03 for ACS355).

Note

According to the ABB Drives Profile a new rising edge of START input will be ignored by the drive until zero speed was reached.

After an emergency stop of the drive a new rising edge of the START input is required to restart the drive.

STOP_COAST (stop coast)

Data type: BOOL

Input STOP_COAST = TRUE will coast the drive immediately (STOP_COAST = inverted Bit 3 of the Control Word – INHIBIT_OP). Setting STOP_COAST=FALSE will restart the drive immediately without need of an rising edge at input START.

RESET (reset)

Data type: BOOL

Input RESET is packed to bit 7 of the Control Word as long as input USE_CW=FALSE. RESET = TRUE resets faults and warnings in the drive. It does not reset the Function Block itself.

SPEED_REF (speed reference)

Data type: REAL

Input SPEED_REF must be given according to ACS3XX / ACX550 drive motor control mode. The motor control mode is set in the drive (e.g. Par. 99.04 for ACS355). In case of a scalar motor control mode (99.04 = 3 for ACS355) the input SPEED_REF reflects the frequency reference in 0.1 Hz (10 = 1Hz). In case of vector speed control mode (99.04 = 2 for ACS35) the input SPEED_REF reflects the speed reference in rpm.

The Function Block includes a linear scaling of input SPEED_REF to the fieldbus equivalent value between -20000 to +20000. 20000 = the value defined in the drive parameter 11.05 (Ref1 Max). This parameter 11.05 is automatically read by the Function Block after a rising edge is given at the input START.

The input range is from negative to positive value of maximum speed (Par.11.05 “Ref1 Max”), e.g. –1500 .. +1500 rpm.

If the input value exceeds the input range, the speed reference value is limited to maximum value. ERR is set to TRUE, ERNO is set to the message that the input of SPEED_REF is out of range. Nevertheless, the Function Block is processed normally.

DRIVE_DATA (drive data)

Data type: ACS_DRIVE_DATA_TYPE ACS_DRIVE_DATA_TYPE Structure to Exchange Data Between Function Blocks for 1 Drive

The combined input/output DRIVE_DATA must be connected to the variable of type ACS_DRIVE_DATA_TYPE of the related ACS drive (slave). Each drive must have its own DRIVE_DATA variable.

The DRIVE_DATA variable contains the data of the drive and must be connected to all related Function Blocks of this drive.

The Function Block ACS_COM_MOD_RTU_ENHANCED reads the Control Word and references (CW, SPEED_REF, REF_VALUE2) from the DRIVE_DATA variable and writes the status information (SW, ACT_SPEED, ACT-VALUE2) to the DRIVE_DATA variable. It also receives requests and data for MODBUS jobs from other Function Blocks e.g. ACS_MOD_READ_N_PRM or ACS_MOD_WRITE_N_PRM via the DRIVE_DATA variable.